topic Re: disk scrub for 11.11 servers in Operating System - HP-UX

disk scrub for 11.11 servers

PamelaJThrasher — Wed, 02 Dec 2009 15:47:38 GMT

I have three 11.11 servers that I will be decommissioning shortly. I would like to clean the disks before the servers are removed from the data center.

I have seen that there is a disk scrub for 11.31. Is there one for 11.11?

If not, what is the best, most secure way to clean the disks?

Thanks,
Pam

Re: disk scrub for 11.11 servers

James R. Ferguson — Wed, 02 Dec 2009 15:53:09 GMT

Hi Pam:

The disk scrub of which you speak isn't available in 11.11. That said, you can do one or more passes of this:

# dd if=/dev/zero of=/dev/rdsk/cXtYdZ bs=1024k

# dd if=/dev/urandom of=/dev/rdsk/cXtYdz bs=1024k

Note the large blocksize and the use of the raw device to bypass the buffer cache.

Generally one pass is sufficient for most purposes. Multiple (>10-15) passes are required to retard the spooks who _really_ want to discover your data.

Of course, as shredder and an acid bath work wonders.

Regards!

...JRF...

Re: disk scrub for 11.11 servers

PamelaJThrasher — Wed, 02 Dec 2009 15:56:17 GMT

Thanks for the prompt response.

Can I login to the server and do this from the command line while the server is up at run level 3? Or do I need to boot it off cd and run this command?

Re: disk scrub for 11.11 servers

Patrick Wallek — Wed, 02 Dec 2009 16:39:30 GMT

>>Can I login to the server and do this from the command line while the server is up at run level 3? Or do I need to boot it off cd and run this command?

You can do this for all disks that are NOT boot disks while the server is at run level 3.

For your boot disks, if you have a similar server, you can take them out of their primary server, insert them into another server and run the 'dd' from there.

Re: disk scrub for 11.11 servers

PamelaJThrasher — Wed, 02 Dec 2009 16:47:54 GMT

In my environment, the only internal disks we have are boot disks. The rest of our disks are on the SAN. The internal disks are the ones that I am look to wipe clean.

There are three servers in all that I am decommissioning.

I could take the internal disks from two of the disks and put them into the third server but that still leaves me with one server's disks that I will not be able to wipe clean with the dd command.

Re: disk scrub for 11.11 servers

James R. Ferguson — Wed, 02 Dec 2009 16:53:04 GMT

Hi (again) Pam:

I'd be less concerned about scrubbing a boot disk than one that had held sensitive data, assuming that its only the operating system contents on the disk. Patrick's suggestion is a good one for that, though.

If you are decommissioning a boot disk, you can start a 'dd' against it that grinds to an end. While the 'dd' runs, recursively remove mountpoints and the kernel ('/stand/vmunix') itself. You won't be booting the disk again.

Regards!

...JRF...

Re: disk scrub for 11.11 servers

Patrick Wallek — Wed, 02 Dec 2009 16:53:18 GMT

If you are really concerned about the data, just destroy the disks. If you have a large magnet, run that over the disks. Other options are: a hammer, a drill (drill THROUGH the entire drive, including disk platters), an acid bath.

Re: disk scrub for 11.11 servers

PamelaJThrasher — Wed, 02 Dec 2009 17:00:19 GMT

Thank you.

Re: disk scrub for 11.11 servers

PamelaJThrasher — Wed, 02 Dec 2009 17:00:33 GMT

Re: disk scrub for 11.11 servers

3M OS Support Team — Thu, 17 Dec 2009 21:13:35 GMT

Jim Garlick's "scrub" version 1.9 was ported to HPUX in 2007 and works great in HPUX 11.11

http://sourceforge.net/projects/diskscrub/files/diskscrub/1.9/disk_scrub_B.1.9_HP-UX_B.11.11_PA.depot/download

Be sure you have a REAL /dev/random. HP has a KRNG* "patch" to create /dev/random.

Scrubbing is slow, but effective.